As a Roblox developer, it is currently impossible to have a shallow terrain water ocean just for looks, where if the player goes underwater, they don’t see… another layer of the ocean?
This is where options for Terrain Vertex Culling should come in.
Devs should have the option to hide the bottom face and top face of both the start and ending of the terrain water.
If Roblox is able to address this issue, it would be nice for the use-case of a shallow ocean where only the top level of the ocean is visible to create the realistic effect of the one true ocean position. Currently, players who go under water can see the floor of the terrain water. (they could go under water with custom swim tools, I disabled automatic swimming hence why I only have a 1 voxel thick ocean)